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1200 Normal Idle Vacuum

Discussion in 'Multistrada' started by FricoRico, Mar 24, 2019.

  1. Hey everyone,

    Last winter I managed to get my hands on a Multistrada 1200, switching from a Monster 1100 EVO. I love riding it, it's so fast and agile. However, when riding during cold weather, regularly riding with a cold engine for long distances I noticed something that bothered me.

    When cruising at around 2000-3000rpm in third gear, the engine cuts power at the slightest change of the throttle. Apparently it sometimes spooks itself and corrects itself causing annoying surging where heavy engine breaking and then recovery occurs.

    At first I thought it was due to the exhaust valve, got it programmed out and removed lambda sensors while at it. It was a little less apparent but still noticeable. Then de-catted it and installed LeoVince mid-pipe. The problem still occurs and is only noticable when engine temperatures are low at around ~60oC.

    I bought myself a CarbTune Pro, to sync the throttle vacuum as per this thread: https://www.ducatiforum.co.uk/threads/throttle-body-balancing-mts-1200.20371/

    The bodies are now nicely synced but I noticed that my idle and slow rev vacuum values are much higher than the pictures in the thread above. At around 30-34cm/hg and maxing out with the slightest rev.

    My question is; should I be worried and tune the air bypass screws to lower the vacuum a bit? Will this increase my riding experience at around 3000rpm?
     
  2. Have you the JPdiag software to see if your throttle pot's are actually balanced?
    I did mine with software and not a vacuum balance
     
    • Like Like x 1
  3. I never heard about the software before. A very useful tool in the toolbox. I think I still have a ELM327 cable laying around. Now to buy a 4-pin Ducati cable to wire it all up.

    I don't think that a hardware vacuum balance is any worse or better, just a bit more work. Can you read realistic vacuum values from the JPDiag software?
     
  4. No, but you can read the throttle values for each cylinder from zero to 100% and can see if they are equal
     
  5. I think you need to drop a gear and keep the revs over 3k until warm - if I read your post correctly
    60degrees at 2k rpm isn’t good for the big twin - get the heat up
     
  6. You struggle in cold weather because the oil cooler is right up font and robs the engine temperature big time!! like early monsters they had a valve that you can manually turn of the oil cooler but the multi does not have this function. I use a piece of card in winter to reduce air flow.
     
  7. Yes, you are both right. Running higher RPMs does indeed lower the issue quite a lot, makes it less apparent. And yes I should create a winter radiator guard that stops from cold air directly hitting the oil cooler, perhaps even the radiator itself.

    Still makes me wonder if the high vacuum is normal behavior, or I should tune more for lower idle vacuum.
     
  8. quick question, do you know how far out your air bleed screws are? Have you altered them
     
  9. have you touched the balance bar screw also?
     
  10. I have not altered the air bleed screws, not sure if the previous owner has but I would find that unlikely.

    I only adjusted the balance bar screws in order to get equal vacuum at both idle and 3000rpm. In both cases vacuum values are about 30-34cm/hg
     
  11. I think you need to start at the basics again. I would see how far out the bleed screws are first, especially in relation to each other. I read loads of stuff whether they should be in 1 turn, 1.5 turns, rear more and so on to the point I did some research and spoke to a couple of mechanics and screwed mine both in fully, this enables the servo stepper motor to adjust the idle anyway, then knowing that both are closed did a TPS re-set, because there are 2, one for each throttle body. I had to get a dealer do this as the JP Diag cant do it. then balanced the throttle bodies by using the JP and adjusting the balance bar screw.
     
  12. Thanks Peter, I've read about turning them in all the way as well. Some people suggested not touching them, others say you should. Guess it doesn't hurt to try and I see a point in your logic.

    Just for my reference, what does turning them in mean? More air bypassing or less air bypassing? Kind of confusing haha, when I receive my diag cable I can also measure current TPS and reset it myself.
     
  13. Yes screw them fully home, clockwise, be careful about doing them up super tight as they have an 'O' ring behind them so don't crush that otherwise they will leak air. Turning them fully home will cause a higher vacuum reading from the bleed screw you are using
     
  14. So last weekend I tuned them fully home. It was about half a turn but the difference is really noticeable. Idle went down quite a lot, I was afraid that it would negatively impact the riding experience even further, but it is actually quite smooth now. Night/day difference.

    I wonder if the TPS reset had any role in smoothing stuff out. Hoping it will stay this way! No more smack in the face when I close the throttle even slightly.
     
  15. Glad you got it sorted.
     
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